The purpose of this project is to design a survey which would measure the prevalence of headache disorders in the United States; to describe the major types of headache by demographic characteristics; to devise a classification system for types of headache, which can be used in epidemiologic studies, using the symptomatology and history reported by patients; to identify the risk factors and other etiological, clinical and environmental factors which may be associated with the occurrence of several major types of headaches; and to to determine the impact of headaches on society. Factors such as financial cost, productivity loss, and quality of life will also be assessed. The survey questionnaire, which includes sections on demography, medical information and history, cost, work and financial loss etc, has been developed. The Feasibility Study has been designed and is not in the data collection stage. Plans for a Pilot Study to validate the questionnaire and to test the methodology are currently being designed.